In known multiprocessor type systems, the machines are generally connected to a common bus over which they communicate with each other and over which they share a certain number of common resources such as memories, consoles, and peripherals for storage on magnetic media.
In spite of the advantages of such a structure, a common bus is limited in capacity to a small number of processors and it is also limited in physical length, further it is highly vulnerable.
Preferred embodiments of the present invention provide a simple type of link, i.e. one which can readily be made highly reliable, capable of interconnecting several tens of processors communicating with each other using a semaphore procedure, e.g. the HDLC type procedure defined in CCITT standard FSO.
Preferred embodiments of the invention also make it possible for a high degree of interchangeability between the processors and between the interfaces, thereby simplifying implementation of software and making it relatively simple to reconfigure an exchange in the event of a breakdown.